Current studies include a double-blind randomized placebo controlled trail of felbamate. The unique three period crossover design allows unbiased estimates of drug effects even in the presence of a carry-over effect from one period to the next. In a separate study of patients with partial seizures, we are evaluating dapsone for its effect in animal models-such as the maximal electroshock--and its protective index is promising. The study will evaluate the pharmacology of the drug in humans, identify drug interactions with current antiepileptic drugs, establish the maximum tolerated dose, and obtain preliminary assessment of efficacy of the drug. This study will be carried out in both inpatient and outpatient facilities, but with outpatient emphasis, and will permit a long-term follow-up of the possible usefulness of this drug in patients with partial seizures. We plan to initiate a study of cysteamine, a drug which has the novel antiepileptic action of reducing levels of somatostatin, which have been reported to be elevated in human seizure foci. Pharmacologic studies continue, focusing on the effects of antiepileptic drug withdrawal.